1. Field of the Invention
The present invention relates to a dustproof panel which prevents dust from adhering to an image display apparatus, such as a cathode ray tube (CRT) or liquid crystal display panel, and more particularly, to a dustproof panel having fewer constituent components, which can be attached and detached by means of a simple installation structure.
2. Description of the Related Art
Conventionally, in an image display apparatus such as a CRT or liquid crystal display monitor, static electricity is liable to occur on the screen and dust is liable to adhere to the screen. When dust adheres to the screen, the screen becomes soiled by the dust and becomes difficult to view. Moreover, when the dust adhering to the screen is wiped away, fine scratches may be produced on the screen. Therefore, when an image display apparatus is used in a location where there is a large amount of dust, the screen is covered with a dustproof panel in order to prevent the adherence of dust to the screen.
For example, in the video industry, images are frequently captured outdoors. Furthermore, in order to check the captured video images, an image display apparatus may be used outdoors. If an image display apparatus is used in a highly dusty location, such as outdoors, without protecting the screen, then the screen is liable to be scratched by dust adhering to the screen. Consequently, in the case of an image display apparatus which is taken outdoors, it is necessary to protect the screen with a dustproof panel in order to avoid the adherence of dust to the screen. Similarly, in an image display apparatus which is incorporated into an apparatus that is used in a highly dusty location, the screen must be protected with a dustproof panel.
Here, an industrial control apparatus is described as one example of an apparatus which is used in a highly dusty location (see, for example, —Japanese Utility Model No. 6-22872).
FIG. 4 is a cross-sectional diagram showing a sectional view of a conventional industrial control apparatus. As shown in FIG. 4, the industrial control apparatus 1 is a console which serves as a man-machine interface. An image display apparatus 30 is disposed inside a steel frame 20, and a dustproof panel 10 is installed on the front face of the frame 20 so as to cover the front face of the screen 40. In order to prevent the adherence of dust to the screen 40, the image display apparatus 30 is sealed by the dustproof panel 10 and the frame 20.
The dustproof panel 10 comprises a dustproof plate 11 and a gasket 12. The gasket 12 is installed in state of tight contact along the edge of the dustproof plate 11 on the rear face of the dustproof plate 11. The dustproof plate 11 is disposed so as to oppose the screen 40. The dustproof plate 11 and the gasket 12 are screw fastened tightly to a frame section 21 which is positioned on the front face of the frame 20, in such a manner that it can be removed easily.
Here, the dustproof plate 11 is a transparent member made of an acrylic resin, for example. The gasket 12 consists of a rigid rubber sponge member having a quadrilateral frame shape or four bar-shaped rigid rubber sponge members which are arranged in a quadrilateral frame shape.
However, with the dustproof panel 10 described above, visibility is impaired due to polarized light caused by the dustproof plate 11. For this reason, when the apparatus is used outdoors where dustproofing is necessary, the dustproof panel 10 is attached to the frame 20 in order to prevent the adherence of dust to the screen 40, whereas when the apparatus is used indoors where dustproofing is not necessary, the dustproof panel 10 may be removed from the frame 20 in order to make the screen 40 easier to view.